Analysis of nucleic acids contained in biological samples, such as blood, plasma, and tissue fragment, is conducted in various fields, including not just academic researches such as biology, biochemistry, and medicine, but also industries for diagnosis, breed improvement for agricultural crops, and food inspection. One of the most widely employed methods for analyzing nucleic acids is PCR (Polymerase Chain Reaction), which is a technology for amplifying a nucleic acid in a region to be analyzed in a base sequence-specific manner. In an application of PCR, a fluorescence label may be attached to the nucleic acid to be analyzed and then irradiated with excitation light to measure fluorescent intensity over time, so that trace amounts of the nucleic acid can be detected with high sensitivity.
In PCR, a solution containing a nucleic acid and a reagent for amplifying the nucleic acid is heated to approximately 95° C. so as to thermally denature the nucleic acid, which is then cooled to approximately 60° C. such that annealing and elongation of the nucleic acid can take place, and this cycle may be repeated 30 to 40 times. In a currently mainstream PCR apparatus, a reaction plate referred to as a “microtiter plate” with 96 to 386 reaction wells is disposed on a Peltier element, and the temperature of the Peltier element is increased and decreased so as to provide a temperature cycle. In this method, however, it takes time to cause a temperature change in the Peltier element itself, posing a problem in decreasing analysis time.
Further, in the above method, a batch process such that a plurality of samples set in the 96 to 386 reaction wells is processed all at once is inevitable. Once a process is started, the next process cannot be started until the first batch is completed.
Non-patent Document 1 discloses a structure such that, in order to solve the problem of increasing the speed of the temperature cycle, a disc-shaped reaction plate with reaction wells is rotated over and in contact with heaters set for a plurality of temperatures in advance. In this example, the need for changing the temperature of the heater is eliminated, so that the temperature of the reaction plate can be changed quickly. Further, in order to facilitate the reception of heat from a temperature adjustment apparatus disposed on an upper side or a lower side, measures are taken to expand a sample solution in a planar direction.    Patent Document 1: JP Patent Publication (Kokai) No. 2008-185389 A    Patent Document 2: U.S. Patent Publication No. 2009/0068064 A1    Non-patent Document: Tsuguto Fujimoto, et al., Jpn. J. Infect. Dis., 63, 31-35 (2010)